Portable video camera and recording apparatus

ABSTRACT

A portable video camera and recording apparatus is comprised of a video camera section and a recording section. The video camera section is comprised of a CCD, analogue-to-digital converters for converting signals from the CCD into digital form. The digital signals are then processed, converted into analogue form, processed in analog form, and then output as the composite video signal. A digital luminance signal and either a digital composite color signal or a plurality of digital color difference signals are received as inputs into the recording section. If the digital composite color signal is received, then the signals are time-base-compressed, converted into analogue form, the composite color signal is frequency converted and filtered and the luminance signal is frequency modulated and filtered. Next, the signals are added together and recorded onto a recording medium. If the digital color difference signals are received, the digital color difference signals are multiplexed together, converted into analogue form, frequency modulated, filtered and then recorded onto one track on the recording medium. The digital luminance signal is time-base-compressed, converted into analogue form, frequency modulated, filtered, and then recorded onto a second track on the recording medium.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to video tape recorders and,more particularly, is directed to a video tape recorder having abuilt-in type camera in which a video camera section and a recordingsection are integrally formed as one body on the same chassis completelyand mechanically.

2. Description of the Prior Art

In a conventional video tape recorder having a built-in type camera, avideo camera section and a recording section are integrally formed asone body on the same chassis, and its signal processing system processesa signal in the form of an analogue signal. Although the signalprocessing system can process the signal in the form of a digitalsignal, a so-called digital video tape recorder in which an input signalis recorded on and/or reproduced from a record medium such as a magnetictape or the like in the form of the digital signal becomes large insize. Therefore, such digital video tape recorder is not suitable forportable use unlike the video tape recorder having a built-in typecamera which is usually carried by the cameraman.

For this reason, a video tape recorder having a built-in type camera isproposed, which is formed by the combination of a camera section inwhich, for example, a signal processing is performed in a digitalfashion and a video tape recorder section in which a signal is processedin an analogue fashion and a signal is recorded and/or reproduced in ananalogue fashion.

This previously-proposed video tape recorder having a built-in typecamera will be described with reference to FIG. 1.

It will be seen in FIG. 1 that an image pickup section, i.e., a camerasection 1 is comprised of an image pickup element and a signalprocessing section while a recording section, i.e., a video taperecorder section is provided, which is generally represented byreference numeral 2. The camera section 1 and the video tape recordersection 2 are integrally formed as one body by some suitable mechanicalcoupling means, though not shown, to form a video tape recorder having abuilt-in type camera. Alternatively, a video tape recorder having abuilt-in type camera might be such that a camera section and a videotape recorder section are perfectly formed within the same chassis.

An image of an object 3 is focused on an image pickup element such as acharge coupled device (CCD) 5 or the like via a lens 4. The CCD 5 isformed as a single plate type in which, for example, R (red), G (green)and B (blue) optical filters, though not shown, are arranged on itsfront in a checkered pattern. The CCD 5 is scanned by a drive signalfrom a CCD driver circuit 6 which is supplied with a reference frequencyfrom a reference signal generator 7. The CCD 5 derives the three primarycolor signals R, G and B. These R, G and B signals generated from theCCD 5 are all in the form of analogue signals and are respectivelysupplied through R, G and B amplifiers 8R, 8G and 8B toanalogue-to-digital (A/D) converters 9R, 9G and 9B, thereby converted todigital signals.

The R, G and B data thus converted to digital signals are supplied to adigital processor circuit 10, in which they undergo digital processings,such as, gamma correction, white clip processing, matrix processing andthe like, thus the R, G and B data are converted to a digital componentluminance signal Y_(D) and digital color difference signals (R-Y)_(D)and (B-Y)_(D). The digital luminance signal Y_(D) is directly suppliedto an adder 12, while the digital color difference signals (R-Y)_(D) and(B-Y)_(D) are supplied to a digital encoder 11, in which they areencoded to a digital chroma signal C_(D) similar to I and Q signals andare interpolated in bit synchronization with the digital luminancesignal Y_(D). The resultant signal is supplied to the adder 12. Theadder 12 is supplied with a vertical synchronizing (sync.) signal and aburst signal from a digital synchronizing signal generator 14 to whichthe reference signal is supplied from the generator 7 and generates adigital composite signal (composite video signal) CS_(D). A samplingclock generator 13 which is supplied with the reference signal from thegenerator 7 is adapted to generate a sampling clock fc=4 fsc which isused to obtain a subcarrier (referred to hereinafter as fsc). Thedigital composite signal CS_(D) from the adder 12 is supplied to adigital-to-analogue (D/A) converter 15 and is thereby converted to ananalogue composite signal in response to a clock 2 fsc supplied theretofrom a terminal T₃.

While the digital luminance signal Y_(d) and the digital chroma signalC_(D) from the digital encoder 11 are digitally added together by theadder 12 as described above, such a variant is also possible that thesedata are converted to analogue signals by a digital-to-analogueconverter and are then added by an adding circuit in an analoguefashion, though not shown.

The analogue composite signal from the digital-to-analogue converter 15is fed through a video output circuit 16 to an output terminal T₁ as,for example, an NTSC analogue composite signal. It is needless to saythat the analogue composite signal may be a PAL or SECAM analoguecomposite signal.

The camera section 1 is provided with a terminal T₂, and the terminal T₂is supplied with an analogue composite signal CS from the video outputcircuit 16.

The video tape recorder section 2 and the camera section 1 areintegrally formed as one body as earlier noted and the video taperecorder section 2 will be described next.

As FIG. 1 shows, the analogue composite signal CS from the terminal T₂of the camera section 1 is supplied to a Y/C separating circuit 17 ofthe video tape recorder section 2, in which it is separated to providean analogue luminance signal Y and an analogue chroma signal C. Theanalogue luminance signal Y is supplied to an FM (frequencymodulation)-modulator 18, in which it is FM-modulated and fed through ahigh-pass filter (HPF) 19 to an adding circuit 20. The analogue chromasignal C from the Y/C separating circuit 17 is supplied to a frequencyconverting circuit 24. The frequency converting circuit 24 is suppliedwith a local oscillation output of, for example, 4.268 MHz from anoscillator 25 and converts the analogue chroma signal C of 3.58 MHz intothe analogue chroma signal C of low frequency, i.e., 688 kHz. The thusfrequency-converted low frequency analogue chroma signal C is suppliedthrough a low-pass filter (LPF) 26 to the adding circuit 20, in which itis frequency-multiplexed with the analogue luminance signal Y. Theresultant signal from the adding circuit 20 is supplied through arecording amplifier 21 to a rotary head 22, thereby recorded on arecording tape 23 as an analogue video signal.

An arrangement of the rotary head 22 is illustrated in FIG. 2A, and asshown in FIG. 2A, the recording tape 23 is obliquely wrapped around atape guide drum 27 in a tape wrapping angle of about 300 degrees in anohm-shape via a pair of tape guide members 28a and 28b in order tominiaturize the rotary head 22 or the video tape recorder section 1.This rotary head 22 is rotated at a field frequency to horizontally scanthe tape 23 at a frequency higher than a normal horizontal scanningfrequency, thereby recording an output signal of the video camera ontracks 29 of the tape 23 as shown in FIG. 2B.

Incidentally, according to the most popular arrangement of theaforementioned rotary head 22, the tape 23 is wrapped around a tapeguide drum in an angular extent slightly larger than 180 degrees and apair of rotary heads 22, mounted on the tape guide drum with an angulardistance of 180 degrees, are rotated at a frame frequency, whereby thetwo rotary heads 22 are alternately brought in contact with the tapethat is transported at a predetermined speed. This type of rotary headis utilized in a portable type video tape recorder which is separatelyprovided from a camera section and it is very difficult to use this typeof rotary head in the video tape recorder having a built-in type camerabecause a tape guide drum and a tape loading mechanism cannot be madelight in weight and small in size.

Further, FIG. 3 shows a professional video tape recorder (e.g., BetaCam, MII, et cetera) which is proposed as an alternative of thearrangement of the video tape recorder section 2. In FIG. 3, like partscorresponding to those of FIG. 1 are marked with the same references andtherefore need not be described in detail.

In FIG. 3, it will be seen that the analogue composite signal CS fromthe terminal T₂ of the camera section 1 is separated to provide theanalogue luminance signal Y and the analogue chroma signal by the Y/Cseparating circuit 17 in the video tape recorder section 2. Thisanalogue luminance signal Y is independently recorded on Y signalrecording tracks of the tape 23 by a Y signal recording head 22. To thisend, the analogue luminance signal Y is FM-modulated by the FM-modulator18 and is supplied through the high-pass filter 19 and the recordingamplifier 21 to the Y signal recording head 22, thereby being recordedon the Y signal recording tracks of the tape 23 by the Y signalrecording head 22. This arrangement can solve the aforementionedproblems, such as, low band of luminance signal and cross modulationwhich are encountered with the low band converted recording system shownin FIG. 1. Red and blue color difference signals R-Y and B-Y involved inthe analogue chroma signal are supplied to a 1/2 time base compressor30. This 1/2 time base compressor 30 is of an analogue type andcompresses the red and blue color difference signals R-Y and B-Y by 1/2under the control of a control circuit 30. Further, according to the 1/2time base compressor 31, the analogue color difference signals R-Y andB-Y are alternately arranged in that order and the thustime-base-compressed color difference signals are FM-modulated by anFM-modulator 32. In that case, the time-base-compressed color differencesignals are supplied through a low-pass filter 33 and atime-base-compressed color difference signal recording amplifier 34 to atime-base-compressed color difference signal recording head 35, therebybeing recorded on a time-base-compressed color difference signalrecording track adjacent to the luminance signal recording track.

An arrangement of the analogue time base compressor 30 is represented inFIG. 4.

As shown in FIG. 4, the time base compressor 30 is comprised of a delaysection 30a formed of four delay elements 30c, 30d, 30e and 30f and aswitch section 30b formed of three switches 30g, 30h and 30i. A delaytime of each of the delay elements 30c, 30d, 30e and 30f is selected tobe 1 H (H is the horizontal scanning period). The first and third delayelements 30c and 30e are supplied with the analogue color differencesignal R-Y through a terminal T₉, and the second and fourth delayelements 30d and 30f are supplied with the analogue color differencesignal B-Y through a terminal T₁ 0. The switch section 30b is providedat the rear stage of these delay elements 30c to 30f in order that thecolor difference signals R-Y and B-Y are selected and alternatelyarranged in the sequential order. In this example, the switch section30b is formed of the first switch 30g which selects the outputs of thefirst and second delay elements 30c and 30d, the second switch 30h whichselects the outputs of the third and fourth delay elements 30e and 30fand the third switch 30i which further selects these selected outputs.The delay section 30a and the switch section 30b are controlled by thecontrol circuit 31 which is supplied with read and write clocks from areference clock generator 29.

In the above-described analogue 1/2 time base compressor 30, the delayelements which are placed in the write mode at every line are selectedsuch that the first and second delay elements 30c and 30d are utilizedin the case that the odd line is in the write mode and that the thirdand fourth delay elements 30e and 30f are utilized in the case that theeven line is in the write mode. During the period in which the third andfourth delay elements 30e and 30f are set in the write mode, the firstand second delay elements 30c and 30d are set in the read mode. At thistime, the frequency of the read clock becomes twice the frequency of thewrite clock by the control circuit 31 so that the input analogue colordifference signals R-Y and B-Y are time-base-compressed by 1/2. Thefirst switch 30g is switched in position such that the first half 0.5 Hof one line is assigned to the read mode of the first delay element 30cand the second half 0.5 H of one line is assigned to the read mode ofthe delay element 30d in order to prevent the read modes of the firstand second delay elements 30c and 30d from overlapping each other. Withrespect to the third and fourth delay elements 30e and 30f, the secondswitch 30h is switched so as to prevent the read modes from overlappingeach other similarly as described above. Thus, when the third switch 30iis switched as shown by a broken line in FIG. 4, the reading operationin the odd line is performed and analogue color difference signals withtime base compressed by 1/2 are obtained. When the switch 30i isswitched as shown by a solid line in FIG. 4, analogue color differencesignals with time base compressed by 1/2 are obtained in the even line.

The compressed color difference signals with the time bases thuscompressed by 1/2 are alternately arranged in the sequential order andfed through the FM modulator 32 to the color difference signal recordinghead 35.

According to the video tape recorder having a built-in type camera shownin FIGS. 1 and 2, the diameter of the tape guide drum 27 can bedecreased by the amount corresponding to the increase of the tapewrapping angle of the tape 23 around the tape guide drum 27 (e.g.,180/300 if the tape wrapping angle is 300 degrees). According to thissystem, the video signal of duration in which the rotary head 22 isrotated by 360 degrees must be time-base-compressed by thetime-base-compressing ratio corresponding to 300 degrees in which therotary head 22 is brought in contact with the tape 23. To this end, thescanning speed of the CCD 5 must be increased. More specifically, sincethe scanning speed of the CCD 5 must be increased under the control ofthe CCD driver circuit 6 thereby to time-base-compress the video signalof one field to 5/6, this signal does not become the standard NTSCcomposite signal. There is then the substantial disadvantage that, evenwhen this signal is supplied to a color monitor receiver as it is, thesynchronization is disabled.

Further, in the conventional video tape recorders having a built-in typecamera shown in FIGS. 1 and 3, the analogue composite video signal CS ofthe camera section 1 is supplied to the video tape recorder section 2 asthe input signal. This analogue composite video signal CS is frequentlyutilized by many video tape recorders such as a home video tape recorderand the like so that, when a signal is transmitted from the camerasection 1 to the video tape recorder section 2 as the composite signalCS, the video tape recorder section 2 side needs the Y/C separatingcircuit 17. When such Y/C separating circuit 17 is utilized, if theluminance signal Y and the chroma signal C are not separated positively,a so-called cross color in which the chroma signal C is mixed into theluminance signal Y occurs. Conversely, the luminance signal Y is mixedinto the chroma signal C so that a dot interference occurs in thepicture at its portion in which the picture is changed rapidly.

Further, in the video tape recorder in which, as shown in FIG. 3, theluminance signal Y is FM-modulated and recorded on one track and thecolor difference signals are time-base-compressed by 1/2 for theluminance signal, FM-modulated and then recorded on the differentrecording track so that a video image of high quality can be obtained,the color difference signals R-Y and B-Y are time-base-compressed by 1/2for the luminance signal Y, which requires the analogue 1/2time-base-compressor 30 and the control circuit 31 which controls theanalogue 1/2 time-base-compressor 30. Also, the arrangement of the 1/2time-base-compressor 30 and the control circuit 31 needs the referenceclock generator 29 or the like and needs a complicated IC circuit.

Furthermore, it is proposed that such time-base-compressor is formed ofa digital memory or the like. In that case, such proposal requires ananalogue-to-digital converter for converting a composite signal into adigital signal in the video tape recorder section 2, which provides alarge and expensive apparatus. There is then the substantialdisadvantage that the conventional video tape recorder having a built-intype camera unavoidably needs a large power source in spite of therequirements in which this type of apparatus should be miniaturized anddriven by a battery power source.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide animproved video tape recorder having a built-in type camera in which theaforementioned shortcomings and disadvantages of the prior art can beeliminated.

More specifically, it is an object of the present invention to provide avideo tape recorder having a built-in type camera in which a videosignal can be prevented from being deteriorated substantially.

It is another object of the present invention to provide a video taperecorder having a built-in type camera which can be miniaturized.

It is a further object of the present invention to provide a video taperecorder having a built-in type camera in which a power consumption canbe reduced.

According to a first aspect of the present invention, a portable videocamera and recording apparatus is comprised of a video camera sectionwhich is comprised of a solid state imager for scanning an input imageand for outputting at least two analogue color video signals,analogue-to-digital converters for converting the analogue color videosignals to digital color video signals, respectively, a first digitalprocessor for processing the digital color video signals and outputtinga digital component video signal which comprises a digital luminancesignal and two digital color difference signals, a second digitalprocessor for processing the digital color difference signals andoutputting a digital composite color signal, and a third digitalprocessor for processing the digital luminance signal and the digitalcomposite color video signal and outputting an analogue composite videosignal, and a recording section is comprised of a firsttime-base-compressing circuit for receiving and time-base-compressingthe digital luminance signal and outputting a digitaltime-base-compressed luminance signal, a second time-base-compressingcircuit for receiving and time-base-compressing the digital compositecolor signal and outputting a digital time-base-compressed compositecolor signal, digital-to-analogue converters for converting the digitaltime-base-compressed luminance signal and the digitaltime-base-compressed composite color signal to analogue signals,respectively, a frequency modulating circuit for frequency-modulatingthe analogue time-base-compressed luminance signal, a frequencyconverter for frequency-converting the analogue time-base-compressedcomposite color signal, an adding circuit for adding the analoguetime-base-compressed luminance signal and analogue time-base-compressedcomposite color signal into a recording video signal, and a transducerfor recording the recording video signal on a recording medium.

As a second aspect of the present invention, a portable video camera andrecording apparatus is comprised of a video camera section which iscomprised of a solid state imager for scanning an input image and foroutputting at least two analogue color video signals,analogue-to-digital converters for converting the analogue color videosignals to digital color video signals, respectively, a first digitalprocessor for processing the digital color video signals and outputtinga digital component video signal which comprises a digital luminancesignal and two digital color difference signals, a second digitalprocessor for processing the digital color difference signals andoutputting a digital composite color signal, and a third digitalprocessor for processing the digital luminance signal and the digitalcomposite color signal and outputting an analogue composite videosignal, and a recording section which is comprised of a firsttime-base-compressing circuit for receiving and time-base-compressingthe digital luminance signal and outputting a digitaltime-base-compressed luminance signal, a multiplexing circuit fortime-multiplexing the digital color difference signals into a digitaltime-multiplexed color difference signal, a first digital-to-analogueconverter for converting the digital time-base-compressed luminancesignal to an analogue time-base-compressed luminance signal, a seconddigital-to-analogue converter for converting the digitaltime-multiplexed color difference signal to an analogue time-multiplexedcolor difference signal, a first frequency modulating circuit forfrequency-modulating the analogue time-base-compressed luminance signal,a second frequency modulating circuit for frequency-modulating theanalogue time-multiplexed color difference signal, a first transducerfor recording the analogue frequency-modulated time-base-compressedluminance signal on a first track on a recording medium, a secondtransducer for recording the analogue frequency-modulatedtime-multiplexed color difference signal on a second track on therecording medium.

The preceding, and other objects, features and advantages of the presentinvention will be apparent in the following detailed description of thepreferred embodiments when read in conjunction with the accompanyingdrawings, in which like reference numerals are used to identify the sameor similar parts in the several views.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an example of a conventional videotape recorder having a built-in type camera;

FIG. 2A is a schematic diagram showing a conventional rotary headassembly used in the prior-art video tape recorder having a built-intype camera shown in FIG. 1;

FIG. 2B is a schematic diagram showing a pattern of recording tracksformed on a tape, and to which reference will be made in explaining anoperation of the conventional video tape recorder having a built-in typecamera;

FIG. 3 is a block diagram showing another example of the conventionalvideo tape recorder having a built-in type camera;

FIG. 4 is a schematic block diagram showing an example of a conventionaltime-base compressing circuit used in the conventional video taperecorder having a built-in type camera shown in FIG. 3;

FIG. 5 is a block diagram showing a first embodiment of a video taperecorder having a built-in type camera according to the presentinvention;

FIG. 6 is a schematic block diagram showing an example of a time-basecompressing circuit used in the video tape recorder having a built-intype camera shown in FIG. 5;

FIGS. 7A-7C are waveform diagrams of signals used to explain anoperation of the circuit shown in FIG. 6;

FIG. 8 is a block diagram showing a second embodiment of the video taperecorder having a built-in type camera according to the presentinvention;

FIGS. 9A-9H are schematic diagrams used to explain a down-samplingoperation of the present invention, respectively; and

FIGS. 10A-10D are schematic diagrams used to explaintime-base-compressing operation and time-multiplexing operation of thepresent invention, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in detail, and initially to FIGS. 5 to 7, afirst embodiment of the video tape recorder having a built-in typecamera according to the present invention will be described. ThroughoutFIGS. 5-7, like parts corresponding to those of FIG. 1 are marked withthe same references and therefore need not be described in detail.

As shown in FIG. 5, the digital luminance signal Y_(D) from the digitalprocessor 10 in the camera section 1 and a digital component signalformed of the digital chroma signal C_(D) such as the I and Q signalsfrom the digital encoder 11 are supplied to intermediate terminals T₄and T₁ 0, respectively and are fed to the video tape recorder section 2.

The digital luminance signal Y_(D) and the digital chroma signal C_(D)from the intermediate terminals T₄ and T₁ 0 are respectively supplied to5/6 time base compressors 36 and 37 each having a field memory shown inFIG. 6. Referring to FIG. 6, each of the 5/6 time base compressors 36and 37 is formed of a digital field memory 42, and as a write samplingclock of this field memory 42, it is possible to use the clock frequencyfc from the sampling clock generator 13 provided at the side of thecamera section 1. A read clock generator 44 is adapted to generate aread clock that is used to control a read-out speed of the memory 42.This read clock generator 44 is supplied with the clock frequency fcfrom the sampling clock generator 13 and increases the read-out clockfrequency 6/5 times the read-out clock frequency fc. This read-out clock6/5 fc is supplied to the memory 42 so that a video signal 45 of onefield period shown in FIG. 7A is read-out from the memory 42 in responseto a read-out clock 46 of frequency 6/5 fc shown in FIG. 7B. Therefore,as shown in FIG. 7C, a signal of one field period (i.e., one sixtieth ofa second) of the video signal 45 is time-base-compressed by a time basecompression ratio corresponding to the angular range (i.e., 300 degrees)in which the tape 23 is wrapped around the guide drum 27 as a videosignal 47.

As described above, the digital luminance signal Y_(D) and the digitalchroma signal C_(D), each of which is time-base-compressed by 5/6, arerespectively supplied to digital-to-analogue converters 38 and 39 andare thereby converted into analogue signals. The analogue luminancesignal Y is FM-modulated by the FM-modulator 18 similarly to FIG. 1while the analogue chroma signal C is frequency-converted similarly toFIG. 1, down converted and added to the luminance signal, thereby beingrecorded on the tape 23 by the rotary head 22.

According to the above-mentioned arrangement, since the scanning speedof the CCD 5 need not be increased, the standard composite signal isobtained from the camera section 1 so that any special monitor apparatusis not required. Further, the 5/6 time base compressors 36 and 37 in thevideo tape recorder 2 side are controlled by a control circuit system inthe camera section 1 side so that the power consumption can be reducedand the video tape recorder having a built-in type camera can beminiaturized.

A second embodiment of the present invention will hereinafter bedescribed with reference to FIG. 8. In the second embodiment shown inFIG. 8, the present invention is applied to a professional video taperecorder having a built-in type camera in which a luminance signal and achroma signal are recorded on different tracks as described inconnection with FIG. 3. In FIG. 8, like parts corresponding to those ofFIG. 5 are marked with the same references and therefore need not bedescribed in detail.

As shown in FIG. 8, the digital luminance signal Y_(D) and the digitalcolor difference signals (R-Y)_(D) and (B-Y)_(D) from the digitalprocessor 10 in the camera section 1 are supplied to intermediateterminals T₄, T₅ and T₆, respectively, and are fed to the video taperecorder section 2.

The digital luminance signal Y_(D) and the digital color differencesignals (R-Y)_(D) and (B-Y)_(D) from the intermediate terminals T₄, T₅and T₆ are supplied to pre-filter and down-sample circuits (referred tohereinafter as PF-DS) 40a, 40b and 40c, respectively. The reason thateach component video signal is down-sampled and converted to a digitalsignal having a half rate is to reduce a storage capacity of a fieldmemory which is utilized in a 5/6 time base compressor, which will bedescribed later, regardless of some deterioration of image quality. If afield memory of mass storage capacity is utilized, it is possible toremove the pre-filtering and the down-sampling.

In the PF-DS circuit 40a, the digital luminance signal Y_(D) ispre-filtered and down-sampled as shown in FIGS. 9A-9D. Similarly, thedigital color difference signals (R-Y)_(D) and (B-Y)_(D) arepre-filtered and down-sampled by the PF-DS circuits 40b and 40c as shownin FIGS. 9E-9H, respectively. Throughout FIGS. 9A-9H, the abscissaindicates fsc and the ordinate indicates level. FIGS. 9A and 9E show,for example, the digital luminance signal Y_(D) =Y₈ (suffix 8 representsthat this luminance signal is the digital signal which is sampled by asampling frequency 8 times or about 8 times the subcarrier frequencyfsc) and color difference signals (R-Y)_(D) =(R-Y)₄, and (B-Y)_(D)=(B-Y)₄ , respectively. FIGS. 9B and 9F show characteristics in whichthe luminance signal Y₈ and the color difference signals (R-Y)₄ and(B-Y)₄ are pre-filtered, respectively. FIGS. 9C and 9G show thecondition that the luminance signal Y₈ and the color difference signals(R-Y).sub. 4 and (B-Y)₄ are down-sampled and a cross over modulation canbe suppressed by down-sampling the luminance signal Y₈ into Y₄ and thecolor difference signals (R-Y)₄ into (R-Y)₂ and the color differencesignal (B-Y)₄ into (B-Y)₂ by 1/2 as shown in FIGS. 9D and 9H. Theluminance signal Y_(D) =Y₄ down-sampled by the PF-DS circuit 40a issupplied to the 5/6 time base compressor 36 similar to that of FIG. 5,in which it is time base compressed by 5/6 and is converted into ananalogue luminance signal Y by the digital-to-analogue converter 38.

The color difference signals (R-Y)_(D) =(R-Y)₂ and (B-Y)_(D) =(B-Y)₂thus down-sampled by the PF-DS circuits 40b and 40c are supplied to 1/2time base compressors 41a and 41b, respectively. Each of the 1/2 timebase compressors 41a and 41b might be formed of a digital field memorysimilarly to the 5/6 time base compressor 36. As a sampling clockgenerator for generating read and write sampling clocks of this fieldmemory and a reference signal generator, those provided at the camerasection 1 side may be used, and alternatively, they may be independentlyprovided at the video tape recorder 2 side. Since the video signalsupplied from the camera section 1 to the video tape recorder section 2is already supplied as digital data, the analogue-to-digital converteror the like need not be provided at the video tape recorder section 2.These 1/2 time base compressors 41a and 41b are supplied at theirterminals T₇ and T₈ with sampling clocks fc=4 fsc and fc/2=2 fsc fromthe sampling clock generator 13.

A method for time-base-compressing these color difference signals(R-Y)_(D) and (B-Y)_(D) by 1/2 will be described with reference to FIGS.10A-10D.

FIG. 10A shows data of the luminance signal Y_(D) of one horizontalscanning period (1 H) from n'th to (n+3)'th lines, and FIGS. 10B and 10Drespectively show signals of the color difference signals (R-Y)_(D) and(B-Y)_(D) of 1 H period from n'th to (n+3)'th lines. In that case, thewrite clock frequency W of the field memory assumes fc/2 and the readclock frequency R thereof assumes fc. Then, the n'th color differencesignal (R-Y)n is time-base-compressed by 1/2. In a like manner, the n'thcolor difference signal (B-Y) is also time-base-compressed by 1/2 andthen delivered. Thus, if a delayed signal is supplied from the 1/2 timebase compressor 41a to the switch 42 so that the delayed signal isdelayed by 0.5 H through a delay element or the like and this switch 42is alternately changed-over, it is possible to obtain a composite colordifference signal CTDM (i.e., chroma time division multiplexed) which istime-base-compressed by 1/2 as shown in FIG. 10C. The thus obtainedcolor difference signal CTDM is supplied to the 5/6 time base compressor37 similar to that of FIG. 5 and is thereby time-base-compressed by 5/6so that one field period is compressed within a range of 300 degrees.The compressed data from the 5/6 time base compressor 37 is supplied toa digital-to-analogue converter 39, in which it is converted into ananalogue signal. The 5/6 time base compressors 36, 37 and thedigital-to-analogue converters 38, 39 are supplied with the write clockfc and the read clock 6/5 fc from the sampling clock generator 13through a terminal T₉ upon writing. Further, while the 1/2 time basecompressors 41a, 41b and the 5/6 time base compressors 36, 37 areindependently provided in the above-described embodiment, it is needlessto say that they may be formed as a 5/12 time base compressor whichperforms 1/2 time-base-compression and 5/6 time-base-compressionsimultaneously.

The analogue luminance signal and analogue color difference signals fromthe analogue-to-digital converters 38 and 39 are respectivelyFM-modulated by the FM-modulators 18 and 32 and are then fed to theluminance signal recording head 22 and the color difference signalrecording head 35, each having different azimuth angle, whereby they aresimultaneously recorded on two tracks. Outputs from the two recordingheads 22 and 35 are recorded on the tape 23 which is obliquely wrappedaround the tape guide drum in an angular extent of substantially 300degrees.

In the second embodiment, similar effects to those of the firstembodiment shown in FIG. 5 can be achieved.

While the color difference signals are converted in the form of analogueto digital signals and are then recorded on the two tracks by two chromasignal and luminance signal rotary heads as described above, the presentinvention can also be applied to such a case that two color differencesignals are converted in the form of digital to analog signals,FM-modulated by two different frequencies, mixed and can be recorded onone track.

According to the video tape recorder having a built-in type camera ofthe present invention, it is possible to obtain the video tape recorderhaving a built-in type camera of compact size in which the deteriorationof video signal is small and a power consumption can be reduced.

Having described preferred embodiments with reference to theaccompanying drawings, it is to be understood that the invention is notlimited to those precise embodiments and that various modifications andvariations thereof could be effected by one skilled in the art withoutdeparting from the spirit or scope of the novel concepts of theinvention as defined in the appended claims.

We claim as our invention:
 1. A video tape recorder having a built-intype camera in which a video camera section and a recording section areintegrally formed as one body comprising:said video camera sectioncomprising: solid state imager means for scanning an input image and foroutputting at least two analogue color video signals;analogue-to-digital converter means for converting said analogue colorvideo signals to digital color video signals, respectively; firstdigital processor means for processing said digital color video signalsand outputting a digital component video signal which comprises adigital luminance signal and two digital color difference signals;second digital processor means for processing said digital colordifference signals and outputting a digital composite color signal; andthird digital processor means for processing said digital luminancesignal and said digital composite color signal and outputting ananalogue composite video signal which is to be supplied to an outputterminal; and said recording section comprising: firsttime-base-compressing means for receiving and time-base-compressing saiddigital luminance signal and outputting a digital time-base-compressedluminance signal; second time-base-compressing means for receiving andtime-base-compressing said digital composite color signal and outputtinga digital time-base-compressed composite color signal; first and seconddigital-to-analogue converter means for converting said digitaltime-base-compressed luminance signal and said digitaltime-base-compressed composite color signal to an analogue time-basecompressed luminance signal and an analogue time-base-compressedcomposite color signal, respectively; frequency modulating means forfrequency-modulating said analogue time-base-compressed luminancesignal; frequency converting means for frequency-converting saidanalogue time-base-compressed composite color signal; adding means foradding the analogue frequency-modulated time-base-compressed luminancesignal and the analogue frequency-converted time-base-compressedcomposite color signal into an analogue time-base-compressed compositevideo signal; and transducer means for recording said analoguetime-base-compressed composite video signal on a recording medium.
 2. Aportable video camera and recording apparatus according to claim 1,wherein said third digital processor means comprises:digital addingmeans for digitally adding said digital luminance signal and saiddigital composite color signal into a digital composite video signal;and second digital-to-analogue converter means for converting saiddigital composite video signal to said analogue composite video signal.3. A portable video camera and recording apparatus according to claim 1,wherein said recording medium is a magnetic tape and said transducermeans is a rotary head which scans said magnetic tape in a range ofn/m×360 degrees around a rotational axis of said rotary head while saidfirst and second time-compressing means time-base-compress said digitalluminance signal and said digital composite color signal respectively byn/m.